I am working for a company for about 4 months and I resigned about half a month back. Since then they are shocked and they are making every little thing an issue. e.g. if i am not completing 9 hrs in office some day then they are saying they would extend my notice period (which is 3 months). If I take a leave then also they are saying the same.Also they constantly threaten to write negatively on my relieving letter and make my background check look bad.

Also I want to inform that there is no where written in the offer letter that if we take leave during notice period, it would be extended.

I have agreed to 3 months notice period they want me to serve but am scared about exploitation on my relieving letter and background check.Kindly suggest.